The expansion of ready-to-eat (RTE) breakfast cereals depends on an unimpeded expansion of the molten starch. Solid insoluble particles like dietary fiber or calcium carbonate interfere with the bubble forming process and thus hamper the extent and direction of the expansion which adversely affect texture or mouthfeel, such as grittiness, surface appearance, and bowl-life of the finished cereal product. For example, the expansion of a twin screw extruded puffed cereal is reduced, product texture is softened, bowl-life is reduced, gritty mouthfeel is created, and surface appearance becomes less smooth and uniform. Dealing with all of these effects is challenging because there are multiple interconnected systemic parameters, such as viscosity and bubble nucleation, and mechanisms, such as rate of hydration and mechanical mixing at work. When RTE cereals are fortified with both fiber and calcium these challenges are further amplified.
U.S. Pat. No. 4,619,831 to Sharma discloses a dietary fiber composition prepared by coating an insoluble fiber, such as enzymatically and chemically purified cereal bran, with a soluble fiber, such as a hydrocolloid, such as pectin or an alginate, where the amount of insoluble dietary fiber is about 92% to about 98.5% based on a dry weight basis of the total composition.
WO 99/65336 to Clark et al discloses agglomerated granules having a granule size of 88 to 2000 microns which when added to an edible composition, substantially do not alter its sensory characteristics, where each agglomerated granule consists of agglomerated particles of a fortificant such as calcium carbonate and a binder which is preferably corn syrup.
WO 00/74501 to Hessel et al discloses wheat bran coated with psyllium, which is coated with pectin, which is coated with insoluble alginate, which is coated with glucose.
U.S. Pat. No. 7,981,453 to Chen et al discloses bran, cellulose, starch, a glucan, or a hydrocolloid in an amount of 45-75% by weight, which is coated with a lipid in an amount of from 10-35% by weight, which is coated with a protein in an amount of from 10-40% by weight.
Starch has been employed for the encapsulation of neutraceuticals, such as vitamins, minerals, fatty acids, and probiotics to prevent their oxidation and for controlled release. These formulations generally employ large amounts of starch for the encapsulation of the readily oxidizable materials, which reduces the amount of the neutraceutical available for incorporation into a foodstuff.
International Patent Publication No. WO 95/26752 (published Oct. 12, 1995) discloses the production of a food product for the enteric supply of a fatty acid, a fatty acid containing substance, an amino acid, or an amino acid containing substance by at least partially complexing the fatty acid or amino acid in the amylose helix of starch to mask the acid. The product may contain one or more flavors and colors, fat soluble substances, anti-oxidants, or pharmacologically effective substances. The components may be first dry mixed and subsequently fed into an extruder where they are substantially mixed and subsequently heated above the gelatinization temperature of the starch to obtain an elasticized mass which is extruded and formed into pellets.
The production of expanded products is disclosed in European patent publication nos. EP 0465364 A1 (published Jan. 8, 1992) and EP 0462012 A2 (published Dec. 18, 1991), U.S. Pat. No. 3,962,416 to Katzen and U.S. Pat. No. 3,786,123 to Katzen. The two European patent publications disclose the production of an anti-obesity food and a method for making it by extrusion of starches with fatty acids into an expanded product having densities between 0.1 and 0.3 g/cm3. U.S. Pat. No. 3,962,416 to Katzen discloses an expanded product which contains at least one nutrient and one gelatinized starch. U.S. Pat. No. 3,786,123 to Katzen discloses a method for producing encapsulated nutrients using extrusion temperatures of between 250° F. and 400° F. and extrusion pressures of between 200 psi to 2500 psi. A high protein encapsulating agent containing up to 40% starch may be used. The starch is gelatinized and extruded into an expanded product.
International Patent Publication No. WO 92/00130 (published Jan. 9, 1992) discloses a continuous process for obtaining an encapsulated, biologically active product in a starchy matrix. A biologically active agent and starch are mixed before extrusion and extruded as a blend, with the encapsulant or biologically active agent being heated together with the starch. Alternatively, a core material to be encapsulated may be added and blended with an aqueous dispersion of starch after the starch and water have been subjected to an elevated temperature sufficient to gelatinize the starch. The extrusion process, it is disclosed, exposes the mix to high shear mechanical action at a temperature above the gelatinization temperature of the starch.
U.S. Pat. No. 5,183,690 to Carr, et al. discloses a continuous process for imparting predetermined release properties to an encapsulated biologically active agent in a matrix of starchy material. The starchy material, an active agent, and water are continuously blended in an ingredient stream wherein the starchy material is at a solids concentration of at least 40%. The ingredients stream is continuously extruded as an extrudate and the extrudate is continuously recovered. The conditions of blending, extruding, and recovering are preselected to yield the predetermined release properties.
U.S. Pat. No. 6,190,591 and International Publication No. WO 98/18610, published on May 7, 1998, both to Bernhard H. van Lengerich, disclose a controlled release particulate composition which contains a hydrophobic component for controlling the release of an encapsulated and/or embedded active component from a plasticized matrix. The controlled release or delayed release composition may be produced without substantial expansion of the matrix material to thereby avoid production of a low density product which prematurely or too rapidly releases the encapsulant or the embedded component.
International Publication No. WO 00/21504 published on Apr. 20, 2000, U.S. Pat. No. 6,500,463 to Van Lengerich, and International Publication No. WO 01/25414 published on Apr. 12, 2001, disclose a continuous process for producing shelf-stable, controlled release, discrete, solid particles from a liquid encapsulant component which contains a sensitive encapsulant, such as a heat sensitive or readily oxidizable pharmaceutically, biologically, or nutritionally active component, such as essential and/or highly unsaturated fatty acids. A liquid encapsulant component which contains an active, sensitive encapsulant, such as a live microorganism or an enzyme dissolved or dispersed in a liquid plasticizer is admixed with a plasticizable matrix material. The matrix material is plasticizable by the liquid plasticizer and the encapsulation of the active encapsulant is accomplished at a low temperature and under low shear conditions.
The present invention provides a method and product for incorporation of a particulate insoluble component, such as dietary fiber and calcium, into an expanded cereal product, without substantial inhibition of expansion of the cereal product by the particulate insoluble component. Solid insoluble particles such as dietary fiber or calcium are pelletized so that they do not interfere with the bubble forming process and do not hamper the extent and direction of the expansion which adversely affect texture or mouthfeel, such as grittiness, surface appearance, and bowl-life of the finished cereal product. Expanded cereal products, such as extruded puffed RTE cereals, produced in accordance with the present invention are fortified with high amounts of solid or particulate insoluble nutritional components such as dietary fiber and calcium but exhibit a crisp, uniform texture and cell structure, improved, prolonged bowl life, non-gritty mouthfeel, and a smooth, uniform surface appearance. The pelletized neutraceutical products contain relatively low amounts of starch or other materials employed for encapsulation of neutraceuticals which increases the amount of the insoluble nutritional component available for fortification of or incorporation into expanded RTE cereal products.